Respiratory motor nerve activites during experimental seizures in cats. Terndrup, Thomas E., Susan L. Knuth, Matthew J. Gdovin, Robert Darnall, Donald Bartlett, Jr. Department of Emergency Medicine, State University of New York, Syracuse, N.Y. and the Department of Physiology, Dartmouth Medical School, Lebanon, N.H.
APStracts 2:0479A, 1995.
We evaluated respiratory motor nerve activities during experimental seizures induced with subcortical penicillin. The activities of the phrenic (PH), nasolabial (NL), and hypoglossal (HG) nerves, and the recurrent laryngeal motor branches to the thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles were analyzed in 13 anesthetized, vagotomized, paralyzed, and ventilated cats. During both ictal and interictal phases of seizures nerve activities became irregular, and peak integrated nerve activities increased, particularly in the case of the PH nerve. The ictal phase of seizures was associated with increased tonic activity and decreased phasic respiratory discharges, particularly in the cases of the HG, NL, and PCA nerves. During some prolonged ictal discharges, entrainment of nerve activities by cortical spiking was associated with irregular, uncoordinated activation, particularly in the TA nerve. These studies help to explain respiratory impairment during seizures by providing evidence of impaired coordination between activation of muscles that regulate upper airway patency and that of the diaphragm. 

Received 5 January 1995; accepted in final form 13 October 1995.
APS Manuscript Number A11-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95